1. Field of the Invention
The present invention relates to a plasma display panel (hereinafter, as PDP) and particularly, to a PDP and a driving method thereof, capable of performing efficient address discharge by generating priming discharge in an address electrode simultaneously sharing upper and lower discharge cells.
2. Description of the Related Art
Generally, as the information processing system has increasingly developed and provided, the importance of the display apparatus as a visual information transmitting means is increased.
As a conventional display device, a Cathode Ray Tube (CRT) has a large volume, and distortion of image by an earth magnetic field is generated. Therefore, it does not fit for the current demands of scale-up, flatting, high luminance, and high efficiency of screens, and researches on various flat panel displays are actively progressed. For instance, a liquid crystal display (hereinafter, as LCD), a field emission display (hereinafter, as FED), a PDP and the like are actively developed as the flat display apparatus.
The PDP displays images including letters or graphics by light emission by ultraviolet rays generated in discharging inert mixed gas such as He+Xe, Ne+Xe, He+Ne+Xe and the like. On the other hand, such PDP can become easily thinner and larger and as the structure is simplified, fabrication is eased. Also, luminance and luminous efficiency is higher when compared with another flat panel display devices. Due to those advantages, researches on the PDP has been actively conducted. Particularly, in a 3-electrode alternating current surface discharge type PDP, since a dielectric layer covers an electrode, a wall charge is stored, and the electrodes are protected from sputtering generated by discharging, thus to enable low voltage driving and long life span.
FIG. 1 is a view showing the conventional 3-electrode surface discharge alternating current PDP (AC PDP).
As shown in FIG. 1, the discharge cells include a pair of sustain electrodes 12Y and 12Z formed on an upper substrate 10 and an address electrode 12X which is formed on a lower substrate 18.
The pair of sustain electrodes 12Y and 12Z are composed of a scan electrode 12Y and a sustain electrode 12Z. Also, the respective pair of sustain electrodes 12Y and 12Z includes a transparent electrode 12a and a bus electrode 12b. 
On the upper substrate 10 in which the sustain electrodes 12Y and 12Z are formed, an upper dielectric layer 14 and a protection layer 16 are formed Here, upper dielectric layer 14 stores a wall charge generated during plasma discharge. Also, the protection layer prevents damage of the upper dielectric layer 14 by sputtering generated in plasma discharge, and improves discharging efficiency of the secondary battery. As the protection layer 16, MgO is commonly used.
A lower dielectric layer 22 for storing the wall charge is formed on the lower glass substrate 18 in which the address electrode 12X is formed. A barrier rib 24 is formed in the upper portion of the lower dielectric layer 22. On the surface of the lower dielectric layer 22 and the barrier rib 24, phosphor 20 is coated. Here, the barrier rib 24 prevents ultraviolet rays and visible rays from crosstalking with a neighboring discharge cell in plasma discharge. The phosphor 20 is excited by ultraviolet rays, thus to generate a visible ray among visible rays corresponding to R, G and B colors.
In the PDP barrier rib 24 is formed in a wall structure of a stripe form. However, in the stripe-type wall structure, exhaust of discharge gas is not easy and coating area of the phosphor 20 is small, thus to lowering luminance.
To solve the problem of the stripe-type barrier rib having the stripe type, a delta-type barrier rib structure was suggested.
FIG. 2 is a plan view showing a PDP having a general delta-type barrier rib.
As shown in FIG. 2, the PDP having the general delta-type barrier rib includes first and second bus electrodes 32Y and 32Z, first transparent electrode 34Y extended from the first bus electrode 32Y and a second transparent electrode 34Z extended from the second bus electrode 34Z. Here, the first transparent electrode 34Y and the first bus electrode 32Y are used as scan electrodes and the second transparent electrode 34Y and the first bus electrode 32Y are used as the scan electrode, and the second transparent electrode 34Z and the second bus electrode 32Z are used as the sustain electrode.
In addition, the delta-type barrier rib 42 includes a plurality of first barrier ribs 36 formed in parallel with the first bus electrode 32Y, and a second barrier rib 38 which is formed while being connected with the first barrier ribs 36 in a perpendicular direction. Here, sub pixels for displaying red, green and blue colors are arranged in a triangular shape by the delta-type barrier rib.
FIG. 3 is an exemplary view showing a structure of an address electrode of the PDP having the delta-type barrier rib shown in FIG. 2.
As shown in FIG. 3, the width of the address electrode 30 is widened in a part corresponding to a discharging space built by the delta-type barrier rib 42 in the PDP having the delta-type barrier rib 42, in the rest area, the width of the address electrode 30 is narrowly formed. Also, the part where the width of the address electrode 30 is positioned below the delta-type barrier rib, thus to prevent crosstalk with the neighboring cells.
FIG. 4 is an exemplary view showing a driving device of a general 3-electrode surface discharge AC PDP.
As shown in FIG. 4, the driving device of the 3-electrode surface discharge AC PDP includes a PDP 50 which is positioned in a matrix form so that mxn discharge cells 51 are connected with scan electrode lines Y1 to Ym, sustain electrode lines Z1 to Zm and address electrode lines X1 to Xn, scan/sustain driving units 52 for driving the scan electrode lines Y1 to Ym, a common sustain driving unit 54 for driving the sustain electrode lines Z1 to Zm, a first address driving unit 56A for driving address electrode lines of ordinal odd numbers X1, X3, . . . , Xn−3, Xn−1, and a second address driving unit 56B for driving address electrode lines of ordinal even numbers X2, X4, . . . , Xn−2, Xn.
Here, the scan/sustain driving unit 52 sequentially supplies scan pulses to the scan electrode lines Y1 to Ym. Also, the scan/sustain driving units 52 supplies sustain pulses to the scan electrode lines Y1 to Ym commonly. The common sustain driving unit 54 supplies sustain pulses to all of the sustain electrode lines Z1 to Zm.
The first and second address driving units 56A and 56B supplies data pulses to the address electrode lines X1 to Xn to be synchronized with the scan pulse. That is, the first address driving unit 56A supplies data pulses to the address electrode lines of ordinal odd numbers X1, X3, . . . , Xn−3, Xn−1, and a second address driving unit 56B supplies data pulses to the address electrode lines of ordinal even numbers X2, X4, . . . , Xn−2, Xn.
FIG. 5 is an exemplary view showing a frame of a general PDP.
As shown in FIG. 5, the PDP is driven by dividing a frame into many sub-fields with different number of discharging to indicate a gray level. The respective sub-field is divided into a reset period for uniformly generating discharging (that is, for uniformly forming the wall charge of the entire cells), an address period for selecting the discharge cells (that is, for forming wall charges in cells of particular position) and a sustain period for indicating the gray scale according to the discharging times.
For instance, in case of displaying images with 256 gray scales, a frame period (16.67 ms) corresponding to 1/60 second (called as ‘1TV field’) is divided into 5 to 8 sub-fields (that is, SF1 to SF8). In addition, the 8 sub-fields are classified into a reset period, an address period and a sustain period again. Here, the reset period and the address period of the respective sub-fields are identical in respective sub-fields and on the other hand, the sustain period is increased at a ratio of 2n in the respective sub-fields.
FIG. 6 is a wave form showing a driving method of a general 3-electrode surface discharge AC PDP.
As shown in FIG. 6, a sub-field is divided into a reset period for initializing an entire screen, an address period for subscribing data while scanning the entire screen by a sequential method and an elimination period for eliminating the sustain period and sustain discharge for maintaining radiated status of the cells in which the data is subscribed.
This will be described as follows.
Firstly, reset pulse (RP) is supplied to the scan electrode lines Y1 to Ym in the reset period. When the reset pulse (RP) is supplied to the scan electrode lines Y1 to Ym, reset discharge is generated between the scan electrode lines Y1 to Ym and the sustain electrode lines Z1 to Zm, thus to initialize the discharge cell.
The scan pulse SP is sequentially applied to the scan electrode lines Y1 to Ym in the address period. Also, the data pulse DP which is synchronized with the scan pulse SP is applied to the address electrode lines X1 to Xn. At this time, address discharge is generated in the discharge cells to which the data pulse DP and scan pulse SP are applied.
First and second sustain pulses SUSPy and SUSPz are supplied to the scan electrode lines Y1 to Ym and sustain electrode lines Z1 to Zm. At this time, sustain discharge is generated in the discharge cells in which the address discharge is generated.
In the elimination period, the elimination pulse EP is supplied to the sustain electrode lines Z1 to Zm. When the elimination pulse EP is supplied to the sustain electrode lines Z1 to Zm, the sustain discharge is eliminated.
On the other hand, to stably maintain plasma discharge, lengths of the scan electrode and sustain electrode must be maintained at a proper level. However, the driving method of the PDP can not efficiently generate discharge since the lengths of the scan electrode lines Y1 to Ym and sustain electrode lines Z1 to Zm are short. In other words, as the resolution of the PDP panel is increased, the size of the discharge cell is decreased, the length to the upper and lower directions becomes shorter than that of the discharge cell including the delta-type barrier rib, and accordingly, a discharging path between the scan electrode lines Y1 to Ym and sustain electrode lines Z1 to Zm facing each other in the orthogonal direction with the address electrode becomes shorter. Therefore, as the resolution of the PDP increases, the driving voltage is increased but the luminance decreases. Also, as the resolution of the PDP panel increases, the number of the scan and sustain electrode lines is increased, and the scanning time for scanning the respective lines is reduced, thus to generate mislighting or misdischarge phenomenon of address discharge.